1. Field of the Invention
This invention relates generally to an apparatus and method for sensing and interpolating image data and, more particularly, to an apparatus and method for sensing sampled image data and thereafter interpolating for the nonsampled image data in a manner that substantially reduces color fringing.
2. Description of the Prior Art
Electronic imaging cameras for recording still images are well known in the art. Such cameras can record a plurality of still images on a single magnetic disk or tape in either analog or digital format for subsequent playback on any well-known cathode ray tube viewing device. Printers may also be utilized with such cameras in a well-known manner to provide hard copy of the recorded images. Such electronic imaging still cameras may utilize two-dimensional image sensing arrays such as charge coupled devices (CCD's) which integrate incident scene light over a predetermined time to provide an electronic information signal corresponding to the scene light intensity incident to the array. Such two-dimensional image sensing arrays comprise a predetermined number of discrete image sensing elements or pixels arranged in a two-dimensional array in which each image sensing element responds to incident illumination to provide an electronic information signal corresponding to the intensity of the incident illumination.
In order to record color images the incident illumination to the two-dimensional image sensing array is filtered so that different image sensing elements received different colored illumination. The filters are arranged in well-known patterns across the face of the image sensing array such as a repeating pattern of red, green and blue stripes. Alternatively, individual image sensing elements or pixels across each line may be filtered in a repeating pattern of red, green, blue, green filters, as is well known in the art. Since each image sensing element can only detect one color of illumination, the color information for the other colors not detected by that image sensing element must be filled in. Filling in the missing color information is generally accomplished by interpolating the detected image data for each color to determine color values for all the colors for each image sensing element.
Conventional types of interpolation, however, can provide images with objectionable aliasing artifacts such as "color fringes" near sharp edges. The conventional approach to solve this problem is to eliminate the color fringes at the expense of image sharpness by blurring (antialiasing) the picture so that the edges are not sharp enough to create a color fringe. Blurring the image in this manner, however, has its obvious disadvantages resulting in a reduction in resolution and a so-called "fuzzy" picture.
Therefore, it is a primary object of this invention to provide an electronic imaging camera which interpolates sampled color image data in a manner that substantially reduces color fringing without the amount of blurring (antialiasing) otherwise required.
It is an even further object of this invention to provide an electronic imaging camera in which sampled image data is interpolated to provide image data in all the colors for all the image sensing elements while minimizing color artifacts without the amount of blurring (antialiasing) otherwise required.
Other objects of the invention will be in part obvious and will in part appear hereinafter. The invention accordingly comprises a mechanism and system possessing the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure.